GB343824A - Improvements relating to explosion chambers for oil switches and the manufacture of the same - Google Patents

Abstract

343,824. Moulding fibrous explosion chambers for electric switches. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.- (Assignees of Peterson, C. F. ; Hill View Park, and Kellogg, C. R.; 128, 6th Street. both in Scotia, New York, and Huber, H. J. H. ; 419, Strathmore Road, Upper Derby, Pennsylvania, both in U.S.A.) April 25, 1930, No. 12806. Convention date, April 25, 1929. [Class 87 (ii).] The explosion chambers for H.T. oil-break electric switches are formed of successive layers of a fibrous material such as paper impregnated with a resinous condensation product which are applied to the sides of a dummy having the approximate form of the interior of the explosion chamber member, portions of the layers being formed over the end of the dummy to make the bottom of the member and the resulting structure is subjected to the simultaneous application of heat and compressive forces against its opposite faces. The explosion chamber 1, which in its finished form is shown in section in Fig. 2, is formed of successive segmental layers of impregnated paper 2, as shown in Fig. 3, which are wound around a dummy 6 and have their edges slitted as shown. The layers are finally kept in position by a securing tape 40 and are then placed in position in the mould shown in Fig. 5 with additional rings of material 41 .. 44, at the ends. The mould is of conical formation having an outer ring 22 within which is secured a ring 23 containing a spiral groove 24 with an inlet and an outlet pipe 25 for the admission of hot water or steam, a segmental die 32 being disposed within. The upper movable pressure member similarly comprises an inner member' secured to the frame 15 and having a spiral groove 29 fed through inlet and outlet pipe 30, the member 28 being secured to an inner die member 27. The laminations are held in position around this die member by centring piece 35 suspended from the frame, the fringed ends of the laminations being suitably formed over the end of the die. Simultaneous heat and pressure are then applied to the laminations of insulating material which are so formed and are of such quantity that in their final compressed position they just fill the surface between the die members and bind together in a solid mass so that after cooling a finished explosion chamber of the form shown in Fig. 2 may be removed from the mould.